Petersburg Granite Virginia Geology

Generalized geologic map of the petersburg batholith in east central virginia.

Petersburg granite virginia geology.

Step back and look at virginia from space and we see a certain degree of complexity. Geologic units in chesterfield county virginia petersburg granite mississippian at surface covers 29 of this area light to dark gray to pink fine to coarse grained equigranular to porphyritic foliated to nonfoliated ranges from granite to granodiorite in composition. Sand gravel and clay are important resources for construction aggregate in this area. The granite contains xenoliths of biotite gneiss and amphibolite.

The granite contains xenoliths of biotite gneiss and amphibolite. Geology is fractal that is the detail and complexity of what we observe remains the same regardless of the scale of observation. The 295 300 ma petersburg batholith in east central virginia forms one of the largest and northernmost of the alleghanian plutonic complexes in the southern appalachian piedmont. From the earliest investigations of the batholith it was recognized that multiple intrusive phases are present.

Multiple intrusive phases are present. Petersburg granite mississippian at surface covers 3 of this area light to dark gray to pink fine to coarse grained equigranular to porphyritic foliated to nonfoliated ranges from granite to granodiorite in composition. Multiple intrusive phases are present. The central part of chesterfield county is underlain by the petersburg granite a large granitic pluton of mississippian age age dated to about 330 million years old.

Jonas 1927 1929 formally named the peterbsurg granite. On the 1928 geologic map of virginia stose 1928 the petersburg granite was designated as precambrian but jonas 1932 later interpreted it to be late paleozoic. Ct chopawamsic terrane gt goochland terrane rt raleigh terrane rrt roanoke rapids terrane. Petersburg granite mississippian at surface covers 20 of this area light to dark gray to pink fine to coarse grained equigranular to porphyritic foliated to nonfoliated ranges from granite to granodiorite in composition.

Light to dark gray to pink fine to coarse grained equigranular to porphyritic foliated to nonfoliated ranges from granite to granodiorite in composition. The batholith is primarily composed of granite including massive and foliated both magmatic and solid state fabrics varieties. Petersburg granite mississippian at surface covers 24 of this area light to dark gray to pink fine to coarse grained equigranular to porphyritic foliated to nonfoliated ranges from granite to granodiorite in composition. Multiple intrusive phases are present.

The petersburg granite forms the bedrock over a large area in east central virginia and one of the best places to see it is along the james river in richmond.